Ecclesiasticism in science is only unfaithfulness to truth

Of moral purpose I see no trace in Nature. That is an article of exclusively human manufacture and very much to our credit.

I wish you would let an old man, who has had his share of fighting, remind you that battles, like hypotheses, are not to be multiplied beyond necessity.

The great thing in the world is not so much to seek happiness as to earn peace and self-respect.

Science has fulfilled her function when she has ascertained and enunciated truth.

Economy does not lie in sparing money, but in spending it wisely.

A good man: body serves his will and enjoys hard work, clear intellect that understands the truths of nature, full of passion for life but controlled by his will, well-developed conscience, loves beauty in art and nature, despises inferior morality, respects himself and others.